In the global market, manufacturers of mass-produced products must offer high quality products at a low price. It is thus important to maximize yield and process efficiency to minimize production costs. This holds especially true in the field of semiconductor fabrication, where it is essential to combine cutting-edge technology with volume production techniques. It is the goal of semiconductor manufacturers to reduce the consumption of raw materials and consumables while at the same time improving process tool utilization.
Chemical Mechanical Planarization (CMP) is a critical unit process for manufacturing of microelectronic and nanoelectronic devices. CMP typically utilizes mechanical abrasion and chemical reactions to remove portions of a semiconductor substrate. For example, CMP is traditionally accomplished by a polishing pad interacting with the semiconductor substrate in the presence of a polishing fluid. The polishing fluid is generally composed of abrasives and other molecular components.
The point at which the CMP process has removed the desired amount of material is commonly referred to as the endpoint of the CMP process. For many processes, this endpoint is reached when portions of an underlying material are exposed by the CMP process. This endpoint is often estimated to be reached after a predefined amount of time at which the semiconductor substrate is exposed to the CMP process. The variability of such set time endpoint detection, however, is often quite high due to changes in polishing pad conditions, variation in the slurry, and variation of incoming thicknesses of material to be removed. Such variation increases tolerances achieved and decreases yield.
Accordingly, it is desirable to provide improved methods and systems for CMP endpoint detection during semiconductor device fabrication. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.